1. Field of the Invention
The invention relates to a process for transvinylation of a carboxylic acid reactant with a vinyl ester reactant to give a vinyl ester product and the corresponding acid of the vinyl ester reactant in the presence of one or more catalysts, wherein the vinyl ester reactant, the carboxylic acid reactant and the catalyst are supplied to a reactor, the transvinylation reaction is conducted and, on completion of the transvinylation reaction, the product vinyl ester is separated by distillation.
2. Description of the Related Art
The transvinylation of carboxylic acids serves to produce vinyl esters. This is understood to mean the transfer of a vinyl unit of a vinyl ester reactant (1V) to a carboxylic acid reactant (2S) to generate a vinyl ester (2V) and the corresponding acid of the reactant vinyl ester reactant (1S).

WO 92/09554 A1 describes a process for catalytic transvinylation in which, after the transvinylation, carboxylic acid reactant and catalyst are removed from the reaction mixture in a first step, and the vinyl ester product is then separated by means of azeotropic distillation after addition of water.
U.S. Pat. No. 5,210,207 describes a transvinylation process by means of reactive distillation, in which, to accelerate the reaction and to increase the selectivity thereof, at least one of the product components is removed from the reaction mixture.
WO 2011/139360 A1 describes a process for continuous catalytic transvinylation of a carboxylic acid with vinyl acetate to give a product vinyl ester and the corresponding acetic acid in a reactive distillation column in which, in order to shift the reaction equilibrium, a mixture of vinyl acetate and acetic acid is removed continuously from the reaction zone. The vinyl ester product is withdrawn from the column tray as a mixture still comprising catalyst and also carboxylic acid reactant and vinyl acetate. This mixture is liquefied in a condenser and the vinyl ester product is removed as a bottom product.
WO 2011/139361 A1 describes a process for semi-continuous catalytic transvinylation of a carboxylic acid with vinyl acetate to give a vinyl ester product and the corresponding acetic acid in a stirred reactor in which, in order to shift the reaction equilibrium, a mixture of vinyl acetate and acetic acid is removed continuously from the reaction zone. The vinyl ester product is withdrawn from the bottom of the stirred reactor as a mixture still comprising catalyst and also carboxylic acid reactant and vinyl acetate. This mixture is then separated by fractional distillation, wherein firstly vinyl acetate is distilled off, and after increasing pressure/temperature, the vinyl ester product is distilled off.
WO 2013/117294 A1 describes a continuous catalytic process for transvinylation of a carboxylic acid with a vinyl ester product to give a vinyl ester product and the corresponding acid. The reaction mixture is fed to a decompression vessel and depressurized to standard pressure therein. The reaction mixture is cooled prior to decompression in order to keep all components liquid as far as possible during the decompression. A gas phase optionally formed is passed into the second separating apparatus. The liquid reaction mixture is then separated in a first separating apparatus wherein a mixture of vinyl ester reactant, vinyl ester product and corresponding acid is removed at the top and is delivered to a second separating apparatus. In the second separating apparatus a mixture of vinyl ester product and corresponding acid is withdrawn at the bottom and fed to a third separating apparatus. The product vinyl ester precipitates in this as bottom product.
WO 2013/117295 A1 describes a continuous catalytic process for transvinylation of a carboxylic acid with a vinyl ester reactant to give a vinyl ester product and the corresponding acid, wherein the corresponding acid is derivatized in a final step. The reaction mixture is fed to a decompression vessel and depressurized to standard pressure therein, wherein the formation of a gas phase is suppressed by cooling. The liquid reaction mixture is then separated in a first separating apparatus wherein a mixture of vinyl ester reactant, vinyl ester product and corresponding acid is removed at the top and is delivered to a second separating apparatus. If a gas phase is formed during the decompression, this is also delivered to the second separating apparatus. In the second separating apparatus a mixture of vinyl ester product and corresponding acid is withdrawn at the bottom and fed to a third separating apparatus. The product vinyl ester precipitates in this apparatus as bottoms product. The acid obtained at the top is derivatized in a downstream process,for example, acetic acid can be reacted with ethylene and oxygen to give vinyl acetate.
WO 2015/078746 A1 and WO 2015/078747 A1 both describe a process for ruthenium-catalyzed transvinylation of a carboxylic acid with a vinyl ester reactant to give a vinyl ester product and the corresponding acid in which, on completion of the transvinylation reaction, the vinyl ester product and the corresponding acid are separated from the reaction mixture by distillation, the vinyl ester product is subsequently separated off by distillation and the remaining reaction mixture is fed back to the reactor.
Due to incomplete reaction during the transvinylation, vinyl ester reactant and carboxylic acid reactant remain in the reaction mixture and, in addition to the target vinyl ester product, the corresponding acid is still released from the vinyl ester reactant. Therefore, in the processes from the prior art, the reaction mixture formed in the transvinylation is usually divided in multi-stage distillation processes into its constituents and the vinyl ester product is isolated. In addition to the apparatus outlay, these separation processes are time-consuming and require a high energy expenditure.
The object consisted therefore of providing a process for catalytic transvinylation of carboxylic acids with which the product vinyl ester is accessible with low complexity but nevertheless with a high degree of purity.